Manufacture of manganese-peroxide anodes



Patented Sept. 30, 1924.

UNITED STATES a 1,510,172. PATENT OFFICE.

MARTIN HOSENFELD, or iaE trN-cHARLorrr'rENRuRq, GERMANY, ASSIGNOR T sIEMENs & HALSKE, AxTrENGEsELLsoHAET, or SIEMENSSTADT, NEAR BERLIN, ,GERMANY, A CORPORATION OF GERMANY.

MANUFACTURE OF 'MANGANESE-PEROXIDE ANODES.

No Drawing.

T 0 all whom it may concern: 4

Be it known that I, MARTIN HOSENFELD, a

citizen of the German Empire, residing at Berlin-Charlottenburg, Germany, have in- 5 vented certain new and useful Improve-- ments in the Manufacture of Manganese- Peroxide Anodes, of which the following is a specification.

It is well known that manganese peroxides 1 or lead peroxide anodes as such or manganese peroxide anodes with a coating of lead peroxide possess great advantages over other anodes as insoluble anodes in the electrolysis with dissolved electrolytes'in acid and particularly in sulphate solution. It has, however, been found that the hitherto known manganese peroxide anodes and manganese peroxide anodes with lead peroxide coatings are comparatively expensive, if produced by the hitherto employed process of manufacture owing to the long time required for carrying through the process and the high cost, the difficulty in producing good contacts, the high cost of the manganese nitrate and the breakage which occurs when the plates are removed from the moulds, finished and transported.

This invention consists of a process for the manufacture of the manganese peroxide anodes and manganese peroxide anodes with lead peroxide coatings, which greatly reduces the production cost and also gives a superior product.

It has been ascertained, that it is not neoessary to make the anodes solid or throughout of manganese peroxide, but that it is possible to make them of a substance, which is for the object in view chemically and also electro-chemically indifferent as a carrier for the manganese peroxide, which is formed by the decomposition of manganese nitrate at temperatures of over 100 C. Hereby a high percentage of the manganese nitrate necessary for the production of the manganese peroxide is saved. The carrier may consist of a porous or rough core such as a plate of infusorial earth, which is saturated or coated. with manganese nitrate and then burned or roasted. The saturation or impregnation may be carried out under a partial vacuum. The carrier may also be formed by mixing the manganese nitrate with a granular substance, which sets during the burning, such as cement, gypsum, clay, sand and the like.

Application filed September 14, 1923. Serial No. 662,754.

In contrast with the hitherto employed processes of manufacture only a fraction of the manganese nitrate formerly used is required in the improved process and consequently only afra ction of the hitherto necessary time of decomposition. The carrier or core for the manganese considerably strengehens the, anodes, so that breakage is almost entirely avoided.

It has also been found that when using porous cores of a material which is chemically and thermically indifi'erent for the purpose in question, it is possible to saturate or coat these porous cores with a paste of ordinary, chemically pure amorphous manganese ore or reduced pebble manganese and manganese nitrate, whereby good conducting manganese peroxide anodes are formed. The amorphous manganese ore is then a good and cheap substitute for the expensive crystalline manganese peroxide by means of which the manufacture of Well conducting, impervious anodes was carried out heretofore. The manganese nitrates hereby only acts as binding agent. Pure amorphous manganese ore together with the manganese nitrate may also be worked into the powdered mass of the substance, which sets during the burning process.

The manufacture of the contacts for carrying the current was hitherto rather difficult, because complicated carbon combs or collars, the production of which required much time and caused considerable waste, had to be burned into the solid manganese peroxide anodes. When employing porous cores the production of the contacts or terminals is considerably simpler. This is carried out in the following manner. On the lower edge of the core is pushed a piece of carbon or graphite provided with a groove. When saturating or impregnating the core or carrier with manganese nitrate a small portion of the nitrate invariably flows between the contacting surfaces and when subsequently the saturated core is burned in this vertical position, the contact piece firmly bakes togetherwith the plate. Upon the burned or baked on piece of carbon or graphite, which along its free longitudinal edge is provided with a dove-tailed or other groove another paraflinated and correspondingly shaped piece of carbon or graphite is pushed.

Anodes constructed of carriers made of powdered substances which become rigid lead peroxide. As electrolytically deposited lead peroxide does not adhere to smooth surfaces the customary solid manganese peroxide anodes produced in moulds could only be coated with lead peroxide on the one rough surface, inasmuch as the other surface was smooth owing to its contact with the mould during the manufacture. The manganese peroxide anodes produced according to the improved process described may owing to their uniformly rough surfaces be electrolytically coated with firmly adhering lead peroxide all over. The burned on contact-head coated with manganese peroxide is also uniformly coated with lead peroxide, whereby an intermediate resistance to the passage of the electric current is effectively avoided.

What I claim as my invention and desire to secure by Letters Patent is:

1. The process for the manufacture of insoluble manganese peroxide anodes suitable for electrolysis with dissolved electrolytes, which consists in preparing a carrier from a chemically and electro-chemically indifferent substance, combining manganese nitrate with said carrier and burning said carrier at temperatures over 100 C. until all the manganese nitrate is converted into manganese peroxide.

2. The process for the manufacture of insoluble manganese peroxide anodes suitable for electrolysis with; dissolved electrolytes, which consists in preparing a carrier from a chemically and electro-chemically indifferent substance, saturating said carrier with manganese nitrate and burning said carrier at temperatures over 100 C. until the manganese nitrate is converted into manganese peroxide.

3. The process for the manufacture of insoluble manganese peroxide anodes suitable for electrolysis with dissolved electrolytes, which consists in 'preparin a carrier from a chemically and electro-c emically indifferent powdery substance which sets on burning mixed with manganese nitrate and burning said carrier at temperatures over 100 (1. until all the manganese nitrate is converted into manganese peroxide.

4fThe process for the manufacture of insoluble manganese eroxide anodes suitable for electrolysis wit dissolved electrolytes, which consists in reparing a carrier rom a chemically and elbctro-chemically indifferent porous substance, saturating said carrier with manganese nitrate, applying a layer of powdered amorphous pebble manganese and manganese nitrate to said carrier and burning said carrier at temperatures over 100 C. until all the manganese nitrate is converted into manganese peroxide.

5. The process for the manufacture of insoluble manganese peroxide anodes suitable for electrolysis with dissolved electrolytes, which consists in preparing a carrier from a chemically and electro-chemically indifferent porous substance, combining manganese nitrate with said carrier, applying suitably shaped carbon contacts to said carriers and burning said carrier at tempera tures over 100 C. until all the manganese nitrate is converted into manganese peroxide.

6. The process for the manufacture of insoluble manganese eroxide anodes suitable for electrolysis witi dissolved electrolytes, which consists in preparing a carrier from a chemically and electro-chemically indifferent substance, combining manganese nitrate with said carrier, burning said carrier at temperature over 100 C. until all the manganese nitrate is converted" into manganese peroxide and then electrolytically coating said anode all over with lead peroxide.

7. The process for the manufacture of insoluble manganese eroxide anodes suitable for electrolysis wit h dissolved electrolytes, which consists in preparing a carrier from a chemically and electro-chemically indifferent porous substance, combining manganese nitrate with said carrier, applying suitably shaped carbon contacts to said carriers and burning said carrier at temperatures over 100 C. until all the manganese nitrate is converted into manganese peroxide, and then electrolytically coating said anode all over with lead peroxide.

In testimony whereof I afiix my signature.

MARTIN HOSENFELD. 

